gserialized2.c

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/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * PostGIS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * PostGIS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PostGIS.  If not, see <http://www.gnu.org/licenses/>.
 *
 **********************************************************************
 *
 * Copyright 2009 Paul Ramsey <pramsey@cleverelephant.ca>
 * Copyright 2017 Darafei Praliaskouski <me@komzpa.net>
 *
 **********************************************************************/
 
/*
*  GSERIALIZED verison 2 includes an optional extended flags uint64_t
*  before the optional bounding box. There may be other optional
*  components before the data area, but they all must be double
*  aligned to that the ordinates remain double aligned.
*
*  <size> size        Used by PgSQL VARSIZE   g->size
*  <srid               3 bytes                g->srid
*   gflags>            1 byte                 g->gflags
*  [<extendedflags>   Optional extended flags (check flags for cue)
*   <extendedflags>]
*  [<bbox-xmin>       Optional bounding box (check flags for cue)
*   <bbox-xmax>       Number of dimensions is variable
*   <bbox-ymin>       and also indicated in the flags
*   <bbox-ymax>]
*  ...
*  data area
*/
 
#include "liblwgeom_internal.h"
#include "lwgeom_log.h"
#include "lwgeodetic.h"
#include "gserialized2.h"
 
/***********************************************************************
* GSERIALIZED metadata utility functions.
*/
 
static int gserialized2_read_gbox_p(const GSERIALIZED *g, GBOX *gbox);
 
 
lwflags_t gserialized2_get_lwflags(const GSERIALIZED *g)
{
        lwflags_t lwflags = 0;
        uint8_t gflags = g->gflags;
        FLAGS_SET_Z(lwflags, G2FLAGS_GET_Z(gflags));
        FLAGS_SET_M(lwflags, G2FLAGS_GET_M(gflags));
        FLAGS_SET_BBOX(lwflags, G2FLAGS_GET_BBOX(gflags));
        FLAGS_SET_GEODETIC(lwflags, G2FLAGS_GET_GEODETIC(gflags));
        if (G2FLAGS_GET_EXTENDED(gflags))
        {
                uint64_t xflags = 0;
                memcpy(&xflags, g->data, sizeof(uint64_t));
                FLAGS_SET_SOLID(lwflags, xflags & G2FLAG_X_SOLID);
        }
        return lwflags;
}
 
static int lwflags_uses_extended_flags(lwflags_t lwflags)
{
        lwflags_t core_lwflags = LWFLAG_Z | LWFLAG_M | LWFLAG_BBOX | LWFLAG_GEODETIC;
        return (lwflags & (~core_lwflags)) != 0;
}
 
 
static inline size_t gserialized2_box_size(const GSERIALIZED *g)
{
        if (G2FLAGS_GET_GEODETIC(g->gflags))
                return 6 * sizeof(float);
        else
                return 2 * G2FLAGS_NDIMS(g->gflags) * sizeof(float);
}
 
static inline size_t gserialized2_header_size(const GSERIALIZED *g)
{
        uint32_t sz = 8; /* varsize (4) + srid(3) + flags (1) */
 
        if (gserialized2_has_extended(g))
                sz += 8;
 
        if (gserialized2_has_bbox(g))
                sz += gserialized2_box_size(g);
 
        return sz;
}
 
/* Returns a pointer to the start of the geometry data */
static inline uint8_t *
gserialized2_get_geometry_p(const GSERIALIZED *g)
{
        uint32_t extra_data_bytes = 0;
        if (gserialized2_has_extended(g))
                extra_data_bytes += sizeof(uint64_t);
 
        if (gserialized2_has_bbox(g))
                extra_data_bytes += gserialized2_box_size(g);
 
        return ((uint8_t *)g->data) + extra_data_bytes;
}
 
uint8_t lwflags_get_g2flags(lwflags_t lwflags)
{
        uint8_t gflags = 0;
        G2FLAGS_SET_Z(gflags, FLAGS_GET_Z(lwflags));
        G2FLAGS_SET_M(gflags, FLAGS_GET_M(lwflags));
        G2FLAGS_SET_BBOX(gflags, FLAGS_GET_BBOX(lwflags));
        G2FLAGS_SET_GEODETIC(gflags, FLAGS_GET_GEODETIC(lwflags));
        G2FLAGS_SET_EXTENDED(gflags, lwflags_uses_extended_flags(lwflags));
        G2FLAGS_SET_VERSION(gflags, 1);
        return gflags;
}
 
/* handle missaligned uint32_t data */
static inline uint32_t gserialized2_get_uint32_t(const uint8_t *loc)
{
        return *((uint32_t*)loc);
}
 
uint8_t g2flags(int has_z, int has_m, int is_geodetic)
{
        uint8_t gflags = 0;
        if (has_z)
                G2FLAGS_SET_Z(gflags, 1);
        if (has_m)
                G2FLAGS_SET_M(gflags, 1);
        if (is_geodetic)
                G2FLAGS_SET_GEODETIC(gflags, 1);
        return gflags;
}
 
int gserialized2_has_bbox(const GSERIALIZED *g)
{
        return G2FLAGS_GET_BBOX(g->gflags);
}
 
int gserialized2_has_extended(const GSERIALIZED *g)
{
        return G2FLAGS_GET_EXTENDED(g->gflags);
}
 
int gserialized2_has_z(const GSERIALIZED *g)
{
        return G2FLAGS_GET_Z(g->gflags);
}
 
int gserialized2_has_m(const GSERIALIZED *g)
{
        return G2FLAGS_GET_M(g->gflags);
}
 
int gserialized2_ndims(const GSERIALIZED *g)
{
        return G2FLAGS_NDIMS(g->gflags);
}
 
int gserialized2_is_geodetic(const GSERIALIZED *g)
{
          return G2FLAGS_GET_GEODETIC(g->gflags);
}
 
uint32_t gserialized2_max_header_size(void)
{
        static const intptr_t size_of_gserialized_up_to_data = (intptr_t) & ((GSERIALIZED *)NULL)->data;
        /* GSERIALIZED size + max bbox according gbox_serialized_size (XYZM*2) + extended flags + type */
        return size_of_gserialized_up_to_data + 8 * sizeof(float) + sizeof(uint64_t) + sizeof(uint32_t);
}
 
 
uint32_t gserialized2_get_type(const GSERIALIZED *g)
{
        uint8_t *ptr = gserialized2_get_geometry_p(g);
        return *((uint32_t*)(ptr));
}
 
int32_t gserialized2_get_srid(const GSERIALIZED *g)
{
        int32_t srid = 0;
        srid = srid | (g->srid[0] << 16);
        srid = srid | (g->srid[1] << 8);
        srid = srid | (g->srid[2]);
        /* Only the first 21 bits are set. Slide up and back to pull
           the negative bits down, if we need them. */
        srid = (srid<<11)>>11;
 
        /* 0 is our internal unknown value. We'll map back and forth here for now */
        if (srid == 0)
                return SRID_UNKNOWN;
        else
                return srid;
}
 
void gserialized2_set_srid(GSERIALIZED *g, int32_t srid)
{
        LWDEBUGF(3, "%s called with srid = %d", __func__, srid);
 
        srid = clamp_srid(srid);
 
        /* 0 is our internal unknown value.
         * We'll map back and forth here for now */
        if (srid == SRID_UNKNOWN)
                srid = 0;
 
        g->srid[0] = (srid & 0x001F0000) >> 16;
        g->srid[1] = (srid & 0x0000FF00) >> 8;
        g->srid[2] = (srid & 0x000000FF);
}
 
static size_t gserialized2_is_empty_recurse(const uint8_t *p, int *isempty);
static size_t gserialized2_is_empty_recurse(const uint8_t *p, int *isempty)
{
        uint32_t type = 0, num = 0;
 
        /* Short circuit if we found any non-empty component */
        if (!*isempty) return 0;
 
        memcpy(&type, p, 4);
        memcpy(&num, p+4, 4);
 
        if (lwtype_is_collection(type))
        {
                /* Recurse into collections */
                size_t lz = 8;
                for ( uint32_t i = 0; i < num; i++ )
                {
                        lz += gserialized2_is_empty_recurse(p+lz, isempty);
                        if (!*isempty)
                                return lz;
                }
                *isempty = LW_TRUE;
                return lz;
        }
        else
        {
                size_t lz = 8;
                /* Any non-collection with zero elements is empty */
                if ( num == 0 )
                {
                        *isempty = LW_TRUE;
                }
                /*
                 * Special case to handle polygon with a non-zero
                 * set of empty rings
                 * https://trac.osgeo.org/postgis/ticket/6028
                 */
                else if ( num > 0 && type == POLYGONTYPE )
                {
                        for ( uint32_t i = 0; i < num; i++ )
                        {
                                uint32_t lrnum;
                                memcpy(&lrnum, p+lz, 4);
                                lz += 4;
                                if ( lrnum > 0 )
                                {
                                        *isempty = LW_FALSE;
                                        return lz;
                                }
                        }
                        *isempty = LW_TRUE;
                }
                /* Any other non-collection with more than zero elements is not empty */
                else
                {
                        *isempty = LW_FALSE;
                }
                return lz;
        }
}
 
int gserialized2_is_empty(const GSERIALIZED *g)
{
        int isempty = LW_TRUE;
        uint8_t *p = gserialized2_get_geometry_p(g);
        gserialized2_is_empty_recurse(p, &isempty);
        return isempty;
}
 
 
/* Prototype for lookup3.c */
/* key = the key to hash */
/* length = length of the key */
/* pc = IN: primary initval, OUT: primary hash */
/* pb = IN: secondary initval, OUT: secondary hash */
void hashlittle2(const void *key, size_t length, uint32_t *pc, uint32_t *pb);
 
int32_t
gserialized2_hash(const GSERIALIZED *g1)
{
        int32_t hval;
        int32_t pb = 0, pc = 0;
        /* Point to just the type/coordinate part of buffer */
        size_t hsz1 = gserialized2_header_size(g1);
        uint8_t *b1 = (uint8_t *)g1 + hsz1;
        /* Calculate size of type/coordinate buffer */
        size_t sz1 = SIZE_GET(g1->size);
        size_t bsz1 = sz1 - hsz1;
        /* Calculate size of srid/type/coordinate buffer */
        int32_t srid = gserialized2_get_srid(g1);
        size_t bsz2 = bsz1 + sizeof(int);
        uint8_t *b2 = lwalloc(bsz2);
        /* Copy srid into front of combined buffer */
        memcpy(b2, &srid, sizeof(int));
        /* Copy type/coordinates into rest of combined buffer */
        memcpy(b2+sizeof(int), b1, bsz1);
        /* Hash combined buffer */
        hashlittle2(b2, bsz2, (uint32_t *)&pb, (uint32_t *)&pc);
        lwfree(b2);
        hval = pb ^ pc;
        return hval;
}
 
 
const float * gserialized2_get_float_box_p(const GSERIALIZED *g, size_t *ndims)
{
        uint8_t *ptr = (uint8_t*)(g->data);
        size_t bndims = G2FLAGS_NDIMS_BOX(g->gflags);
 
        if (ndims)
                *ndims = bndims;
 
        /* Cannot do anything if there's no box */
        if (!(g && gserialized_has_bbox(g)))
                return NULL;
 
        /* Advance past optional extended flags */
        if (gserialized2_has_extended(g))
                ptr += 8;
 
        return (const float *)(ptr);
}
 
int gserialized2_read_gbox_p(const GSERIALIZED *g, GBOX *gbox)
{
        uint8_t gflags = g->gflags;
        /* Null input! */
        if (!(g && gbox)) return LW_FAILURE;
 
        /* Initialize the flags on the box */
        gbox->flags = gserialized2_get_lwflags(g);
 
        /* Has pre-calculated box */
        if (G2FLAGS_GET_BBOX(gflags))
        {
                int i = 0;
                const float *fbox = gserialized2_get_float_box_p(g, NULL);
                gbox->xmin = fbox[i++];
                gbox->xmax = fbox[i++];
                gbox->ymin = fbox[i++];
                gbox->ymax = fbox[i++];
 
                /* Geodetic? Read next dimension (geocentric Z) and return */
                if (G2FLAGS_GET_GEODETIC(gflags))
                {
                        gbox->zmin = fbox[i++];
                        gbox->zmax = fbox[i++];
                        return LW_SUCCESS;
                }
                /* Cartesian? Read extra dimensions (if there) and return */
                if (G2FLAGS_GET_Z(gflags))
                {
                        gbox->zmin = fbox[i++];
                        gbox->zmax = fbox[i++];
                }
                if (G2FLAGS_GET_M(gflags))
                {
                        gbox->mmin = fbox[i++];
                        gbox->mmax = fbox[i++];
                }
                return LW_SUCCESS;
        }
        return LW_FAILURE;
}
 
/*
* Populate a bounding box *without* allocating an LWGEOM. Useful
* for some performance purposes.
*/
int
gserialized2_peek_gbox_p(const GSERIALIZED *g, GBOX *gbox)
{
        uint32_t type = gserialized2_get_type(g);
        uint8_t *geometry_start = gserialized2_get_geometry_p(g);
        double *dptr = (double *)(geometry_start);
        int32_t *iptr = (int32_t *)(geometry_start);
 
        /* Peeking doesn't help if you already have a box or are geodetic */
        if (G2FLAGS_GET_GEODETIC(g->gflags) || G2FLAGS_GET_BBOX(g->gflags))
        {
                return LW_FAILURE;
        }
 
        /* Boxes of points are easy peasy */
        if (type == POINTTYPE)
        {
                int i = 1; /* Start past <pointtype><padding> */
 
                /* Read the npoints flag */
                int isempty = (iptr[1] == 0);
 
                /* EMPTY point has no box */
                if (isempty) return LW_FAILURE;
 
                gbox->xmin = gbox->xmax = dptr[i++];
                gbox->ymin = gbox->ymax = dptr[i++];
                gbox->flags = gserialized2_get_lwflags(g);
                if (G2FLAGS_GET_Z(g->gflags))
                {
                        gbox->zmin = gbox->zmax = dptr[i++];
                }
                if (G2FLAGS_GET_M(g->gflags))
                {
                        gbox->mmin = gbox->mmax = dptr[i++];
                }
                gbox_float_round(gbox);
                return LW_SUCCESS;
        }
        /* We can calculate the box of a two-point cartesian line trivially */
        else if (type == LINETYPE)
        {
                int ndims = G2FLAGS_NDIMS(g->gflags);
                int i = 0; /* Start at <linetype><npoints> */
                int npoints = iptr[1]; /* Read the npoints */
 
                /* This only works with 2-point lines */
                if (npoints != 2)
                        return LW_FAILURE;
 
                /* Advance to X */
                /* Past <linetype><npoints> */
                i++;
                gbox->xmin = FP_MIN(dptr[i], dptr[i+ndims]);
                gbox->xmax = FP_MAX(dptr[i], dptr[i+ndims]);
 
                /* Advance to Y */
                i++;
                gbox->ymin = FP_MIN(dptr[i], dptr[i+ndims]);
                gbox->ymax = FP_MAX(dptr[i], dptr[i+ndims]);
 
                gbox->flags = gserialized2_get_lwflags(g);
                if (G2FLAGS_GET_Z(g->gflags))
                {
                        /* Advance to Z */
                        i++;
                        gbox->zmin = FP_MIN(dptr[i], dptr[i+ndims]);
                        gbox->zmax = FP_MAX(dptr[i], dptr[i+ndims]);
                }
                if (G2FLAGS_GET_M(g->gflags))
                {
                        /* Advance to M */
                        i++;
                        gbox->mmin = FP_MIN(dptr[i], dptr[i+ndims]);
                        gbox->mmax = FP_MAX(dptr[i], dptr[i+ndims]);
                }
                gbox_float_round(gbox);
                return LW_SUCCESS;
        }
        /* We can also do single-entry multi-points */
        else if (type == MULTIPOINTTYPE)
        {
                int i = 0; /* Start at <multipointtype><ngeoms> */
                int ngeoms = iptr[1]; /* Read the ngeoms */
                int npoints;
 
                /* This only works with single-entry multipoints */
                if (ngeoms != 1)
                        return LW_FAILURE;
 
                /* Npoints is at <multipointtype><ngeoms><pointtype><npoints> */
                npoints = iptr[3];
 
                /* The check below is necessary because we can have a MULTIPOINT
                 * that contains a single, empty POINT (ngeoms = 1, npoints = 0) */
                if (npoints != 1)
                        return LW_FAILURE;
 
                /* Move forward two doubles (four ints) */
                /* Past <multipointtype><ngeoms> */
                /* Past <pointtype><npoints> */
                i += 2;
 
                /* Read the doubles from the one point */
                gbox->xmin = gbox->xmax = dptr[i++];
                gbox->ymin = gbox->ymax = dptr[i++];
                gbox->flags = gserialized2_get_lwflags(g);
                if (G2FLAGS_GET_Z(g->gflags))
                {
                        gbox->zmin = gbox->zmax = dptr[i++];
                }
                if (G2FLAGS_GET_M(g->gflags))
                {
                        gbox->mmin = gbox->mmax = dptr[i++];
                }
                gbox_float_round(gbox);
                return LW_SUCCESS;
        }
        /* And we can do single-entry multi-lines with two vertices (!!!) */
        else if (type == MULTILINETYPE)
        {
                int ndims = G2FLAGS_NDIMS(g->gflags);
                int i = 0; /* Start at <multilinetype><ngeoms> */
                int ngeoms = iptr[1]; /* Read the ngeoms */
                int npoints;
 
                /* This only works with 1-line multilines */
                if (ngeoms != 1)
                        return LW_FAILURE;
 
                /* Npoints is at <multilinetype><ngeoms><linetype><npoints> */
                npoints = iptr[3];
 
                if (npoints != 2)
                        return LW_FAILURE;
 
                /* Advance to X */
                /* Move forward two doubles (four ints) */
                /* Past <multilinetype><ngeoms> */
                /* Past <linetype><npoints> */
                i += 2;
                gbox->xmin = FP_MIN(dptr[i], dptr[i+ndims]);
                gbox->xmax = FP_MAX(dptr[i], dptr[i+ndims]);
 
                /* Advance to Y */
                i++;
                gbox->ymin = FP_MIN(dptr[i], dptr[i+ndims]);
                gbox->ymax = FP_MAX(dptr[i], dptr[i+ndims]);
 
                gbox->flags = gserialized2_get_lwflags(g);
                if (G2FLAGS_GET_Z(g->gflags))
                {
                        /* Advance to Z */
                        i++;
                        gbox->zmin = FP_MIN(dptr[i], dptr[i+ndims]);
                        gbox->zmax = FP_MAX(dptr[i], dptr[i+ndims]);
                }
                if (G2FLAGS_GET_M(g->gflags))
                {
                        /* Advance to M */
                        i++;
                        gbox->mmin = FP_MIN(dptr[i], dptr[i+ndims]);
                        gbox->mmax = FP_MAX(dptr[i], dptr[i+ndims]);
                }
                gbox_float_round(gbox);
                return LW_SUCCESS;
        }
 
        return LW_FAILURE;
}
 
static inline void
gserialized2_copy_point(double *dptr, lwflags_t flags, POINT4D *out_point)
{
        uint8_t dim = 0;
        out_point->x = dptr[dim++];
        out_point->y = dptr[dim++];
 
        if (G2FLAGS_GET_Z(flags))
        {
                out_point->z = dptr[dim++];
        }
        if (G2FLAGS_GET_M(flags))
        {
                out_point->m = dptr[dim];
        }
}
 
int
gserialized2_peek_first_point(const GSERIALIZED *g, POINT4D *out_point)
{
        uint8_t *geometry_start = gserialized2_get_geometry_p(g);
 
        uint32_t isEmpty = (((uint32_t *)geometry_start)[1]) == 0;
        if (isEmpty)
        {
                return LW_FAILURE;
        }
 
        uint32_t type = (((uint32_t *)geometry_start)[0]);
        /* Setup double_array_start depending on the geometry type */
        double *double_array_start = NULL;
        switch (type)
        {
        case (POINTTYPE):
                /* For points we only need to jump over the type and npoints 32b ints */
                double_array_start = (double *)(geometry_start + 2 * sizeof(uint32_t));
                break;
 
        default:
                lwerror("%s is currently not implemented for type %d", __func__, type);
                return LW_FAILURE;
        }
 
        gserialized2_copy_point(double_array_start, g->gflags, out_point);
        return LW_SUCCESS;
}
 
int gserialized2_get_gbox_p(const GSERIALIZED *g, GBOX *box)
{
        /* Try to just read the serialized box. */
        if (gserialized2_read_gbox_p(g, box) == LW_SUCCESS)
        {
                return LW_SUCCESS;
        }
        /* No box? Try to peek into simpler geometries and */
        /* derive a box without creating an lwgeom */
        else if (gserialized2_peek_gbox_p(g, box) == LW_SUCCESS)
        {
                return LW_SUCCESS;
        }
        /* Damn! Nothing for it but to create an lwgeom... */
        /* See http://trac.osgeo.org/postgis/ticket/1023 */
        else
        {
                LWGEOM *lwgeom = lwgeom_from_gserialized(g);
                int ret = lwgeom_calculate_gbox(lwgeom, box);
                gbox_float_round(box);
                lwgeom_free(lwgeom);
                return ret;
        }
}
 
int gserialized2_fast_gbox_p(const GSERIALIZED *g, GBOX *box)
{
        /* Try to just read the serialized box. */
        if (gserialized2_read_gbox_p(g, box) == LW_SUCCESS)
        {
                return LW_SUCCESS;
        }
        /* No box? Try to peek into simpler geometries and */
        /* derive a box without creating an lwgeom */
        else if (gserialized2_peek_gbox_p(g, box) == LW_SUCCESS)
        {
                return LW_SUCCESS;
        }
        else
        {
                return LW_FAILURE;
        }
}
 
 
 
 
/***********************************************************************
* Calculate the GSERIALIZED size for an LWGEOM.
*/
 
/* Private functions */
 
static size_t gserialized2_from_any_size(const LWGEOM *geom); /* Local prototype */
 
static size_t gserialized2_from_lwpoint_size(const LWPOINT *point)
{
        size_t size = 4; /* Type number. */
 
        assert(point);
 
        size += 4; /* Number of points (one or zero (empty)). */
        size += point->point->npoints * FLAGS_NDIMS(point->flags) * sizeof(double);
 
        LWDEBUGF(3, "point size = %d", size);
 
        return size;
}
 
static size_t gserialized2_from_lwline_size(const LWLINE *line)
{
        size_t size = 4; /* Type number. */
 
        assert(line);
 
        size += 4; /* Number of points (zero => empty). */
        size += line->points->npoints * FLAGS_NDIMS(line->flags) * sizeof(double);
 
        LWDEBUGF(3, "linestring size = %d", size);
 
        return size;
}
 
static size_t gserialized2_from_lwtriangle_size(const LWTRIANGLE *triangle)
{
        size_t size = 4; /* Type number. */
 
        assert(triangle);
 
        size += 4; /* Number of points (zero => empty). */
        size += triangle->points->npoints * FLAGS_NDIMS(triangle->flags) * sizeof(double);
 
        LWDEBUGF(3, "triangle size = %d", size);
 
        return size;
}
 
static size_t gserialized2_from_lwpoly_size(const LWPOLY *poly)
{
        size_t size = 4; /* Type number. */
        uint32_t i = 0;
 
        assert(poly);
 
        size += 4; /* Number of rings (zero => empty). */
        if (poly->nrings % 2)
                size += 4; /* Padding to double alignment. */
 
        for (i = 0; i < poly->nrings; i++)
        {
                size += 4; /* Number of points in ring. */
                size += poly->rings[i]->npoints * FLAGS_NDIMS(poly->flags) * sizeof(double);
        }
 
        LWDEBUGF(3, "polygon size = %d", size);
 
        return size;
}
 
static size_t gserialized2_from_lwcircstring_size(const LWCIRCSTRING *curve)
{
        size_t size = 4; /* Type number. */
 
        assert(curve);
 
        size += 4; /* Number of points (zero => empty). */
        size += curve->points->npoints * FLAGS_NDIMS(curve->flags) * sizeof(double);
 
        LWDEBUGF(3, "circstring size = %d", size);
 
        return size;
}
 
static size_t gserialized2_from_lwcollection_size(const LWCOLLECTION *col)
{
        size_t size = 4; /* Type number. */
        uint32_t i = 0;
 
        assert(col);
 
        size += 4; /* Number of sub-geometries (zero => empty). */
 
        for (i = 0; i < col->ngeoms; i++)
        {
                size_t subsize = gserialized2_from_any_size(col->geoms[i]);
                size += subsize;
                LWDEBUGF(3, "lwcollection subgeom(%d) size = %d", i, subsize);
        }
 
        LWDEBUGF(3, "lwcollection size = %d", size);
 
        return size;
}
 
static size_t gserialized2_from_any_size(const LWGEOM *geom)
{
        LWDEBUGF(2, "Input type: %s", lwtype_name(geom->type));
 
        switch (geom->type)
        {
        case POINTTYPE:
                return gserialized2_from_lwpoint_size((LWPOINT *)geom);
        case LINETYPE:
                return gserialized2_from_lwline_size((LWLINE *)geom);
        case POLYGONTYPE:
                return gserialized2_from_lwpoly_size((LWPOLY *)geom);
        case TRIANGLETYPE:
                return gserialized2_from_lwtriangle_size((LWTRIANGLE *)geom);
        case CIRCSTRINGTYPE:
                return gserialized2_from_lwcircstring_size((LWCIRCSTRING *)geom);
        case CURVEPOLYTYPE:
        case COMPOUNDTYPE:
        case MULTIPOINTTYPE:
        case MULTILINETYPE:
        case MULTICURVETYPE:
        case MULTIPOLYGONTYPE:
        case MULTISURFACETYPE:
        case POLYHEDRALSURFACETYPE:
        case TINTYPE:
        case COLLECTIONTYPE:
                return gserialized2_from_lwcollection_size((LWCOLLECTION *)geom);
        default:
                lwerror("Unknown geometry type: %d - %s", geom->type, lwtype_name(geom->type));
                return 0;
        }
}
 
/* Public function */
 
size_t gserialized2_from_lwgeom_size(const LWGEOM *geom)
{
        size_t size = 8; /* Header overhead (varsize+flags+srid) */
        assert(geom);
 
        /* Reserve space for extended flags */
        if (lwflags_uses_extended_flags(geom->flags))
                size += 8;
 
        /* Reserve space for bounding box */
        if (geom->bbox)
                size += gbox_serialized_size(geom->flags);
 
        size += gserialized2_from_any_size(geom);
        LWDEBUGF(3, "%s size = %d", __func__, size);
 
        return size;
}
 
/***********************************************************************
* Serialize an LWGEOM into GSERIALIZED.
*/
 
/* Private functions */
 
static size_t gserialized2_from_lwgeom_any(const LWGEOM *geom, uint8_t *buf);
 
static size_t gserialized2_from_lwpoint(const LWPOINT *point, uint8_t *buf)
{
        uint8_t *loc;
        int ptsize = ptarray_point_size(point->point);
        int type = POINTTYPE;
 
        assert(point);
        assert(buf);
 
        if (FLAGS_GET_ZM(point->flags) != FLAGS_GET_ZM(point->point->flags))
                lwerror("Dimensions mismatch in lwpoint");
 
        LWDEBUGF(2, "%s (%p, %p) called", __func__, point, buf);
 
        loc = buf;
 
        /* Write in the type. */
        memcpy(loc, &type, sizeof(uint32_t));
        loc += sizeof(uint32_t);
        /* Write in the number of points (0 => empty). */
        memcpy(loc, &(point->point->npoints), sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        /* Copy in the ordinates. */
        if (point->point->npoints > 0)
        {
                memcpy(loc, getPoint_internal(point->point, 0), ptsize);
                loc += ptsize;
        }
 
        return (size_t)(loc - buf);
}
 
static size_t gserialized2_from_lwline(const LWLINE *line, uint8_t *buf)
{
        uint8_t *loc;
        int ptsize;
        size_t size;
        int type = LINETYPE;
 
        assert(line);
        assert(buf);
 
        LWDEBUGF(2, "%s (%p, %p) called", __func__, line, buf);
 
        if (FLAGS_GET_Z(line->flags) != FLAGS_GET_Z(line->points->flags))
                lwerror("Dimensions mismatch in lwline");
 
        ptsize = ptarray_point_size(line->points);
 
        loc = buf;
 
        /* Write in the type. */
        memcpy(loc, &type, sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        /* Write in the npoints. */
        memcpy(loc, &(line->points->npoints), sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        LWDEBUGF(3, "%s added npoints (%d)", __func__, line->points->npoints);
 
        /* Copy in the ordinates. */
        if (line->points->npoints > 0)
        {
                size = line->points->npoints * ptsize;
                memcpy(loc, getPoint_internal(line->points, 0), size);
                loc += size;
        }
        LWDEBUGF(3, "%s copied serialized_pointlist (%d bytes)", __func__, ptsize * line->points->npoints);
 
        return (size_t)(loc - buf);
}
 
static size_t gserialized2_from_lwpoly(const LWPOLY *poly, uint8_t *buf)
{
        uint32_t i;
        uint8_t *loc;
        int ptsize;
        int type = POLYGONTYPE;
 
        assert(poly);
        assert(buf);
 
        LWDEBUGF(2, "%s called", __func__);
 
        ptsize = sizeof(double) * FLAGS_NDIMS(poly->flags);
        loc = buf;
 
        /* Write in the type. */
        memcpy(loc, &type, sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        /* Write in the nrings. */
        memcpy(loc, &(poly->nrings), sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        /* Write in the npoints per ring. */
        for (i = 0; i < poly->nrings; i++)
        {
                memcpy(loc, &(poly->rings[i]->npoints), sizeof(uint32_t));
                loc += sizeof(uint32_t);
        }
 
        /* Add in padding if necessary to remain double aligned. */
        if (poly->nrings % 2)
        {
                memset(loc, 0, sizeof(uint32_t));
                loc += sizeof(uint32_t);
        }
 
        /* Copy in the ordinates. */
        for (i = 0; i < poly->nrings; i++)
        {
                POINTARRAY *pa = poly->rings[i];
                size_t pasize;
 
                if (FLAGS_GET_ZM(poly->flags) != FLAGS_GET_ZM(pa->flags))
                        lwerror("Dimensions mismatch in lwpoly");
 
                pasize = pa->npoints * ptsize;
                if ( pa->npoints > 0 )
                        memcpy(loc, getPoint_internal(pa, 0), pasize);
                loc += pasize;
        }
        return (size_t)(loc - buf);
}
 
static size_t gserialized2_from_lwtriangle(const LWTRIANGLE *triangle, uint8_t *buf)
{
        uint8_t *loc;
        int ptsize;
        size_t size;
        int type = TRIANGLETYPE;
 
        assert(triangle);
        assert(buf);
 
        LWDEBUGF(2, "%s (%p, %p) called", __func__, triangle, buf);
 
        if (FLAGS_GET_ZM(triangle->flags) != FLAGS_GET_ZM(triangle->points->flags))
                lwerror("Dimensions mismatch in lwtriangle");
 
        ptsize = ptarray_point_size(triangle->points);
 
        loc = buf;
 
        /* Write in the type. */
        memcpy(loc, &type, sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        /* Write in the npoints. */
        memcpy(loc, &(triangle->points->npoints), sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        LWDEBUGF(3, "%s added npoints (%d)", __func__, triangle->points->npoints);
 
        /* Copy in the ordinates. */
        if (triangle->points->npoints > 0)
        {
                size = triangle->points->npoints * ptsize;
                memcpy(loc, getPoint_internal(triangle->points, 0), size);
                loc += size;
        }
        LWDEBUGF(3, "%s copied serialized_pointlist (%d bytes)", __func__, ptsize * triangle->points->npoints);
 
        return (size_t)(loc - buf);
}
 
static size_t gserialized2_from_lwcircstring(const LWCIRCSTRING *curve, uint8_t *buf)
{
        uint8_t *loc;
        int ptsize;
        size_t size;
        int type = CIRCSTRINGTYPE;
 
        assert(curve);
        assert(buf);
 
        if (FLAGS_GET_ZM(curve->flags) != FLAGS_GET_ZM(curve->points->flags))
                lwerror("Dimensions mismatch in lwcircstring");
 
 
        ptsize = ptarray_point_size(curve->points);
        loc = buf;
 
        /* Write in the type. */
        memcpy(loc, &type, sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        /* Write in the npoints. */
        memcpy(loc, &curve->points->npoints, sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        /* Copy in the ordinates. */
        if (curve->points->npoints > 0)
        {
                size = curve->points->npoints * ptsize;
                memcpy(loc, getPoint_internal(curve->points, 0), size);
                loc += size;
        }
 
        return (size_t)(loc - buf);
}
 
static size_t gserialized2_from_lwcollection(const LWCOLLECTION *coll, uint8_t *buf)
{
        size_t subsize = 0;
        uint8_t *loc;
        uint32_t i;
        int type;
 
        assert(coll);
        assert(buf);
 
        type = coll->type;
        loc = buf;
 
        /* Write in the type. */
        memcpy(loc, &type, sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        /* Write in the number of subgeoms. */
        memcpy(loc, &coll->ngeoms, sizeof(uint32_t));
        loc += sizeof(uint32_t);
 
        /* Serialize subgeoms. */
        for (i = 0; i < coll->ngeoms; i++)
        {
                if (FLAGS_GET_ZM(coll->flags) != FLAGS_GET_ZM(coll->geoms[i]->flags))
                        lwerror("Dimensions mismatch in lwcollection");
                subsize = gserialized2_from_lwgeom_any(coll->geoms[i], loc);
                loc += subsize;
        }
 
        return (size_t)(loc - buf);
}
 
static size_t gserialized2_from_lwgeom_any(const LWGEOM *geom, uint8_t *buf)
{
        assert(geom);
        assert(buf);
 
        LWDEBUGF(2, "Input type (%d) %s, hasz: %d hasm: %d",
                geom->type, lwtype_name(geom->type),
                FLAGS_GET_Z(geom->flags), FLAGS_GET_M(geom->flags));
        LWDEBUGF(2, "LWGEOM(%p) uint8_t(%p)", geom, buf);
 
        switch (geom->type)
        {
        case POINTTYPE:
                return gserialized2_from_lwpoint((LWPOINT *)geom, buf);
        case LINETYPE:
                return gserialized2_from_lwline((LWLINE *)geom, buf);
        case POLYGONTYPE:
                return gserialized2_from_lwpoly((LWPOLY *)geom, buf);
        case TRIANGLETYPE:
                return gserialized2_from_lwtriangle((LWTRIANGLE *)geom, buf);
        case CIRCSTRINGTYPE:
                return gserialized2_from_lwcircstring((LWCIRCSTRING *)geom, buf);
        case CURVEPOLYTYPE:
        case COMPOUNDTYPE:
        case MULTIPOINTTYPE:
        case MULTILINETYPE:
        case MULTICURVETYPE:
        case MULTIPOLYGONTYPE:
        case MULTISURFACETYPE:
        case POLYHEDRALSURFACETYPE:
        case TINTYPE:
        case COLLECTIONTYPE:
                return gserialized2_from_lwcollection((LWCOLLECTION *)geom, buf);
        default:
                lwerror("Unknown geometry type: %d - %s", geom->type, lwtype_name(geom->type));
                return 0;
        }
        return 0;
}
 
static size_t gserialized2_from_extended_flags(lwflags_t lwflags, uint8_t *buf)
{
        if (lwflags_uses_extended_flags(lwflags))
        {
                uint64_t xflags = 0;
                if (FLAGS_GET_SOLID(lwflags))
                        xflags |= G2FLAG_X_SOLID;
 
                // G2FLAG_X_CHECKED_VALID
                // G2FLAG_X_IS_VALID
                // G2FLAG_X_HAS_HASH
 
                memcpy(buf, &xflags, sizeof(uint64_t));
                return sizeof(uint64_t);
        }
        return 0;
}
 
static size_t gserialized2_from_gbox(const GBOX *gbox, uint8_t *buf)
{
        uint8_t *loc = buf;
        float f;
        size_t return_size;
 
        assert(buf);
 
        f = next_float_down(gbox->xmin);
        memcpy(loc, &f, sizeof(float));
        loc += sizeof(float);
 
        f = next_float_up(gbox->xmax);
        memcpy(loc, &f, sizeof(float));
        loc += sizeof(float);
 
        f = next_float_down(gbox->ymin);
        memcpy(loc, &f, sizeof(float));
        loc += sizeof(float);
 
        f = next_float_up(gbox->ymax);
        memcpy(loc, &f, sizeof(float));
        loc += sizeof(float);
 
        if (FLAGS_GET_GEODETIC(gbox->flags))
        {
                f = next_float_down(gbox->zmin);
                memcpy(loc, &f, sizeof(float));
                loc += sizeof(float);
 
                f = next_float_up(gbox->zmax);
                memcpy(loc, &f, sizeof(float));
                loc += sizeof(float);
 
                return_size = (size_t)(loc - buf);
                LWDEBUGF(4, "returning size %d", return_size);
                return return_size;
        }
 
        if (FLAGS_GET_Z(gbox->flags))
        {
                f = next_float_down(gbox->zmin);
                memcpy(loc, &f, sizeof(float));
                loc += sizeof(float);
 
                f = next_float_up(gbox->zmax);
                memcpy(loc, &f, sizeof(float));
                loc += sizeof(float);
 
        }
 
        if (FLAGS_GET_M(gbox->flags))
        {
                f = next_float_down(gbox->mmin);
                memcpy(loc, &f, sizeof(float));
                loc += sizeof(float);
 
                f = next_float_up(gbox->mmax);
                memcpy(loc, &f, sizeof(float));
                loc += sizeof(float);
        }
        return_size = (size_t)(loc - buf);
        LWDEBUGF(4, "returning size %d", return_size);
        return return_size;
}
 
/* Public function */
 
GSERIALIZED* gserialized2_from_lwgeom(LWGEOM *geom, size_t *size)
{
        size_t expected_size = 0;
        size_t return_size = 0;
        uint8_t *ptr = NULL;
        GSERIALIZED *g = NULL;
        assert(geom);
 
        /*
        ** See if we need a bounding box, add one if we don't have one.
        */
        if ((!geom->bbox) && lwgeom_needs_bbox(geom) && (!lwgeom_is_empty(geom)))
        {
                lwgeom_add_bbox(geom);
        }
 
        /*
        ** Harmonize the flags to the state of the lwgeom
        */
        FLAGS_SET_BBOX(geom->flags, (geom->bbox ? 1 : 0));
 
        /* Set up the uint8_t buffer into which we are going to write the serialized geometry. */
        expected_size = gserialized2_from_lwgeom_size(geom);
        ptr = lwalloc(expected_size);
        g = (GSERIALIZED*)(ptr);
 
        /* Set the SRID! */
        gserialized2_set_srid(g, geom->srid);
        /*
        ** We are aping PgSQL code here, PostGIS code should use
        ** VARSIZE to set this for real.
        */
        SIZE_SET(g->size, expected_size);
        g->gflags = lwflags_get_g2flags(geom->flags);
 
        /* Move write head past size, srid and flags. */
        ptr += 8;
 
        /* Write in the extended flags if necessary */
        ptr += gserialized2_from_extended_flags(geom->flags, ptr);
 
        /* Write in the serialized form of the gbox, if necessary. */
        if (geom->bbox)
                ptr += gserialized2_from_gbox(geom->bbox, ptr);
 
        /* Write in the serialized form of the geometry. */
        ptr += gserialized2_from_lwgeom_any(geom, ptr);
 
        /* Calculate size as returned by data processing functions. */
        return_size = ptr - (uint8_t*)g;
 
        if (expected_size != return_size) /* Uh oh! */
        {
                lwerror("Return size (%lu) not equal to expected size (%lu)!", return_size, expected_size);
                return NULL;
        }
 
        if (size) /* Return the output size to the caller if necessary. */
                *size = return_size;
 
        return g;
}
 
// xxxx continue reviewing extended flags content from here
 
/***********************************************************************
* De-serialize GSERIALIZED into an LWGEOM.
*/
 
static LWGEOM* lwgeom_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size);
 
static LWPOINT* lwpoint_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size)
{
        uint8_t *start_ptr = data_ptr;
        LWPOINT *point;
        uint32_t npoints = 0;
 
        assert(data_ptr);
 
        point = (LWPOINT*)lwalloc(sizeof(LWPOINT));
        point->srid = SRID_UNKNOWN; /* Default */
        point->bbox = NULL;
        point->type = POINTTYPE;
        point->flags = lwflags;
 
        data_ptr += 4; /* Skip past the type. */
        npoints = gserialized2_get_uint32_t(data_ptr); /* Zero => empty geometry */
        data_ptr += 4; /* Skip past the npoints. */
 
        if (npoints > 0)
                point->point = ptarray_construct_reference_data(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), 1, data_ptr);
        else
                point->point = ptarray_construct(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), 0); /* Empty point */
 
        data_ptr += npoints * FLAGS_NDIMS(lwflags) * sizeof(double);
 
        if (size)
                *size = data_ptr - start_ptr;
 
        return point;
}
 
static LWLINE* lwline_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size)
{
        uint8_t *start_ptr = data_ptr;
        LWLINE *line;
        uint32_t npoints = 0;
 
        assert(data_ptr);
 
        line = (LWLINE*)lwalloc(sizeof(LWLINE));
        line->srid = SRID_UNKNOWN; /* Default */
        line->bbox = NULL;
        line->type = LINETYPE;
        line->flags = lwflags;
 
        data_ptr += 4; /* Skip past the type. */
        npoints = gserialized2_get_uint32_t(data_ptr); /* Zero => empty geometry */
        data_ptr += 4; /* Skip past the npoints. */
 
        if (npoints > 0)
                line->points = ptarray_construct_reference_data(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), npoints, data_ptr);
 
        else
                line->points = ptarray_construct(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), 0); /* Empty linestring */
 
        data_ptr += FLAGS_NDIMS(lwflags) * npoints * sizeof(double);
 
        if (size)
                *size = data_ptr - start_ptr;
 
        return line;
}
 
static LWPOLY* lwpoly_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size)
{
        uint8_t *start_ptr = data_ptr;
        LWPOLY *poly;
        uint8_t *ordinate_ptr;
        uint32_t nrings = 0;
        uint32_t i = 0;
 
        assert(data_ptr);
 
        poly = (LWPOLY*)lwalloc(sizeof(LWPOLY));
        poly->srid = SRID_UNKNOWN; /* Default */
        poly->bbox = NULL;
        poly->type = POLYGONTYPE;
        poly->flags = lwflags;
 
        data_ptr += 4; /* Skip past the polygontype. */
        nrings = gserialized2_get_uint32_t(data_ptr); /* Zero => empty geometry */
        poly->nrings = nrings;
        LWDEBUGF(4, "nrings = %d", nrings);
        data_ptr += 4; /* Skip past the nrings. */
 
        ordinate_ptr = data_ptr; /* Start the ordinate pointer. */
        if (nrings > 0)
        {
                poly->rings = (POINTARRAY**)lwalloc( sizeof(POINTARRAY*) * nrings );
                poly->maxrings = nrings;
                ordinate_ptr += nrings * 4; /* Move past all the npoints values. */
                if (nrings % 2) /* If there is padding, move past that too. */
                        ordinate_ptr += 4;
        }
        else /* Empty polygon */
        {
                poly->rings = NULL;
                poly->maxrings = 0;
        }
 
        for (i = 0; i < nrings; i++)
        {
                uint32_t npoints = 0;
 
                /* Read in the number of points. */
                npoints = gserialized2_get_uint32_t(data_ptr);
                data_ptr += 4;
 
                /* Make a point array for the ring, and move the ordinate pointer past the ring ordinates. */
                poly->rings[i] = ptarray_construct_reference_data(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), npoints, ordinate_ptr);
 
                ordinate_ptr += sizeof(double) * FLAGS_NDIMS(lwflags) * npoints;
        }
 
        if (size)
                *size = ordinate_ptr - start_ptr;
 
        return poly;
}
 
static LWTRIANGLE* lwtriangle_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size)
{
        uint8_t *start_ptr = data_ptr;
        LWTRIANGLE *triangle;
        uint32_t npoints = 0;
 
        assert(data_ptr);
 
        triangle = (LWTRIANGLE*)lwalloc(sizeof(LWTRIANGLE));
        triangle->srid = SRID_UNKNOWN; /* Default */
        triangle->bbox = NULL;
        triangle->type = TRIANGLETYPE;
        triangle->flags = lwflags;
 
        data_ptr += 4; /* Skip past the type. */
        npoints = gserialized2_get_uint32_t(data_ptr); /* Zero => empty geometry */
        data_ptr += 4; /* Skip past the npoints. */
 
        if (npoints > 0)
                triangle->points = ptarray_construct_reference_data(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), npoints, data_ptr);
        else
                triangle->points = ptarray_construct(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), 0); /* Empty triangle */
 
        data_ptr += FLAGS_NDIMS(lwflags) * npoints * sizeof(double);
 
        if (size)
                *size = data_ptr - start_ptr;
 
        return triangle;
}
 
static LWCIRCSTRING* lwcircstring_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size)
{
        uint8_t *start_ptr = data_ptr;
        LWCIRCSTRING *circstring;
        uint32_t npoints = 0;
 
        assert(data_ptr);
 
        circstring = (LWCIRCSTRING*)lwalloc(sizeof(LWCIRCSTRING));
        circstring->srid = SRID_UNKNOWN; /* Default */
        circstring->bbox = NULL;
        circstring->type = CIRCSTRINGTYPE;
        circstring->flags = lwflags;
 
        data_ptr += 4; /* Skip past the circstringtype. */
        npoints = gserialized2_get_uint32_t(data_ptr); /* Zero => empty geometry */
        data_ptr += 4; /* Skip past the npoints. */
 
        if (npoints > 0)
                circstring->points = ptarray_construct_reference_data(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), npoints, data_ptr);
        else
                circstring->points = ptarray_construct(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), 0); /* Empty circularstring */
 
        data_ptr += FLAGS_NDIMS(lwflags) * npoints * sizeof(double);
 
        if (size)
                *size = data_ptr - start_ptr;
 
        return circstring;
}
 
static LWCOLLECTION* lwcollection_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size)
{
        uint32_t type;
        uint8_t *start_ptr = data_ptr;
        LWCOLLECTION *collection;
        uint32_t ngeoms = 0;
        uint32_t i = 0;
 
        assert(data_ptr);
 
        type = gserialized2_get_uint32_t(data_ptr);
        data_ptr += 4; /* Skip past the type. */
 
        collection = (LWCOLLECTION*)lwalloc(sizeof(LWCOLLECTION));
        collection->srid = SRID_UNKNOWN; /* Default */
        collection->bbox = NULL;
        collection->type = type;
        collection->flags = lwflags;
 
        ngeoms = gserialized2_get_uint32_t(data_ptr);
        collection->ngeoms = ngeoms; /* Zero => empty geometry */
        data_ptr += 4; /* Skip past the ngeoms. */
 
        if (ngeoms > 0)
        {
                collection->geoms = lwalloc(sizeof(LWGEOM*) * ngeoms);
                collection->maxgeoms = ngeoms;
        }
        else
        {
                collection->geoms = NULL;
                collection->maxgeoms = 0;
        }
 
        /* Sub-geometries are never de-serialized with boxes (#1254) */
        FLAGS_SET_BBOX(lwflags, 0);
 
        for (i = 0; i < ngeoms; i++)
        {
                uint32_t subtype = gserialized2_get_uint32_t(data_ptr);
                size_t subsize = 0;
 
                if (!lwcollection_allows_subtype(type, subtype))
                {
                        lwerror("Invalid subtype (%s) for collection type (%s)", lwtype_name(subtype), lwtype_name(type));
                        lwfree(collection);
                        return NULL;
                }
                collection->geoms[i] = lwgeom_from_gserialized2_buffer(data_ptr, lwflags, &subsize);
                data_ptr += subsize;
        }
 
        if (size)
                *size = data_ptr - start_ptr;
 
        return collection;
}
 
LWGEOM* lwgeom_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *g_size)
{
        uint32_t type;
 
        assert(data_ptr);
 
        type = gserialized2_get_uint32_t(data_ptr);
 
        LWDEBUGF(2, "Got type %d (%s), hasz=%d hasm=%d geodetic=%d hasbox=%d", type, lwtype_name(type),
                FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), FLAGS_GET_GEODETIC(lwflags), FLAGS_GET_BBOX(lwflags));
 
        switch (type)
        {
        case POINTTYPE:
                return (LWGEOM *)lwpoint_from_gserialized2_buffer(data_ptr, lwflags, g_size);
        case LINETYPE:
                return (LWGEOM *)lwline_from_gserialized2_buffer(data_ptr, lwflags, g_size);
        case CIRCSTRINGTYPE:
                return (LWGEOM *)lwcircstring_from_gserialized2_buffer(data_ptr, lwflags, g_size);
        case POLYGONTYPE:
                return (LWGEOM *)lwpoly_from_gserialized2_buffer(data_ptr, lwflags, g_size);
        case TRIANGLETYPE:
                return (LWGEOM *)lwtriangle_from_gserialized2_buffer(data_ptr, lwflags, g_size);
        case MULTIPOINTTYPE:
        case MULTILINETYPE:
        case MULTIPOLYGONTYPE:
        case COMPOUNDTYPE:
        case CURVEPOLYTYPE:
        case MULTICURVETYPE:
        case MULTISURFACETYPE:
        case POLYHEDRALSURFACETYPE:
        case TINTYPE:
        case COLLECTIONTYPE:
                return (LWGEOM *)lwcollection_from_gserialized2_buffer(data_ptr, lwflags, g_size);
        default:
                lwerror("Unknown geometry type: %d - %s", type, lwtype_name(type));
                return NULL;
        }
}
 
LWGEOM* lwgeom_from_gserialized2(const GSERIALIZED *g)
{
        lwflags_t lwflags = 0;
        int32_t srid = 0;
        uint32_t lwtype = 0;
        uint8_t *data_ptr = NULL;
        LWGEOM *lwgeom = NULL;
        GBOX bbox;
        size_t size = 0;
 
        assert(g);
 
        srid = gserialized2_get_srid(g);
        lwtype = gserialized2_get_type(g);
        lwflags = gserialized2_get_lwflags(g);
 
        LWDEBUGF(4, "Got type %d (%s), srid=%d", lwtype, lwtype_name(lwtype), srid);
 
        data_ptr = (uint8_t*)g->data;
 
        /* Skip optional flags */
        if (G2FLAGS_GET_EXTENDED(g->gflags))
        {
                data_ptr += sizeof(uint64_t);
        }
 
        /* Skip over optional bounding box */
        if (FLAGS_GET_BBOX(lwflags))
                data_ptr += gbox_serialized_size(lwflags);
 
        lwgeom = lwgeom_from_gserialized2_buffer(data_ptr, lwflags, &size);
 
        if (!lwgeom)
                lwerror("%s: unable create geometry", __func__); /* Ooops! */
 
        lwgeom->type = lwtype;
        lwgeom->flags = lwflags;
 
        if (gserialized2_read_gbox_p(g, &bbox) == LW_SUCCESS)
        {
                lwgeom->bbox = gbox_copy(&bbox);
        }
        else if (lwgeom_needs_bbox(lwgeom) && (lwgeom_calculate_gbox(lwgeom, &bbox) == LW_SUCCESS))
        {
                lwgeom->bbox = gbox_copy(&bbox);
        }
        else
        {
                lwgeom->bbox = NULL;
        }
 
        lwgeom_set_srid(lwgeom, srid);
 
        return lwgeom;
}
 
GSERIALIZED* gserialized2_set_gbox(GSERIALIZED *g, GBOX *gbox)
{
 
        int g_ndims = G2FLAGS_NDIMS_BOX(g->gflags);
        int box_ndims = FLAGS_NDIMS_BOX(gbox->flags);
        GSERIALIZED *g_out = NULL;
        size_t box_size = 2 * g_ndims * sizeof(float);
        float *fbox;
        int fbox_pos = 0;
 
        /* The dimensionality of the inputs has to match or we are SOL. */
        if (g_ndims != box_ndims)
        {
                return NULL;
        }
 
        /* Serialized already has room for a box. */
        if (G2FLAGS_GET_BBOX(g->gflags))
        {
                g_out = g;
        }
        /* Serialized has no box. We need to allocate enough space for the old
           data plus the box, and leave a gap in the memory segment to write
           the new values into.
        */
        else
        {
                size_t varsize_in = SIZE_GET(g->size);
                size_t varsize_out = varsize_in + box_size;
                uint8_t *ptr_out, *ptr_in, *ptr;
                g_out = lwalloc(varsize_out);
                ptr_out = (uint8_t*)g_out;
                ptr = ptr_in = (uint8_t*)g;
                /* Copy the head of g into place */
                memcpy(ptr_out, ptr_in, 8); ptr_out += 8; ptr_in += 8;
                /* Optionally copy extended bit into place */
                if (G2FLAGS_GET_EXTENDED(g->gflags))
                {
                        memcpy(ptr_out, ptr_in, 8); ptr_out += 8; ptr_in += 8;
                }
                /* Copy the body of g into place after leaving space for the box */
                ptr_out += box_size;
                memcpy(ptr_out, ptr_in, varsize_in - (ptr_in - ptr));
                G2FLAGS_SET_BBOX(g_out->gflags, 1);
                SIZE_SET(g_out->size, varsize_out);
        }
 
        /* Move bounds to nearest float values */
        gbox_float_round(gbox);
        /* Now write the float box values into the memory segement */
        fbox = (float*)(g_out->data);
        /* Copy in X/Y */
        fbox[fbox_pos++] = gbox->xmin;
        fbox[fbox_pos++] = gbox->xmax;
        fbox[fbox_pos++] = gbox->ymin;
        fbox[fbox_pos++] = gbox->ymax;
        /* Optionally copy in higher dims */
        if(gserialized2_has_z(g) || gserialized2_is_geodetic(g))
        {
                fbox[fbox_pos++] = gbox->zmin;
                fbox[fbox_pos++] = gbox->zmax;
        }
        if(gserialized2_has_m(g) && ! gserialized2_is_geodetic(g))
        {
                fbox[fbox_pos++] = gbox->mmin;
                fbox[fbox_pos++] = gbox->mmax;
        }
 
        return g_out;
}
 
 
GSERIALIZED* gserialized2_drop_gbox(GSERIALIZED *g)
{
        int g_ndims = G2FLAGS_NDIMS_BOX(g->gflags);
        size_t box_size = 2 * g_ndims * sizeof(float);
        size_t g_out_size = SIZE_GET(g->size) - box_size;
        GSERIALIZED *g_out = lwalloc(g_out_size);
 
        /* Copy the contents while omitting the box */
        if (G2FLAGS_GET_BBOX(g->gflags))
        {
                uint8_t *outptr = (uint8_t*)g_out;
                uint8_t *inptr = (uint8_t*)g;
                /* Copy the header (size+type) of g into place */
                memcpy(outptr, inptr, 8); outptr += 8; inptr += 8;
                /* Copy extended flags, if there are any */
                if (G2FLAGS_GET_EXTENDED(g->gflags))
                {
                        memcpy(outptr, inptr, 8); outptr += 8; inptr += 8;
                }
                /* Advance past box */
                inptr += box_size;
                /* Copy parts after the box into place */
                memcpy(outptr, inptr, g_out_size - 8);
                G2FLAGS_SET_BBOX(g_out->gflags, 0);
                SIZE_SET(g_out->size, g_out_size);
        }
        /* No box? Nothing to do but copy and return. */
        else
        {
                memcpy(g_out, g, g_out_size);
        }
 
        return g_out;
}